I'm trying make a query with HQL that will stay with the same order as given list of IDs. I know it's possible with SQL but I can't find any way to do it with HQL (and I cannot do it with native SQL because I got many joins)
Example
fingerIds = [3,1,10,4]
SELECT p FROM People p
JOIN FETCH p.fingers f
WHERE f.id IN :fingerIds
DB: PostgreSQL 10.4
Hibernate: 4.3.11.Final
Eg. Given list of IDs: [3,1,10,4]
Actual result's order: [1,3,4,10]
Expected result's order: [3,1,10,4]
You can obtain the order by adding to your query the keyword FIELD, in your example:
SELECT p FROM People p
JOIN FETCH p.fingers f
WHERE f.id IN :fingerIds
ORDER BY FIELD(f.ID,3,1,10,4)
Ofc you can replace the numbers with your variable :fingerIds
You can find more about that command here.
Returns the index (position) of str in the str1, str2, str3, ... list. Returns 0 if str is not found.
Related
I have a collection in Azure CosmosDB where each document has 2 fields, say
{"a":1,"b":2}
{"a":1,"b":3}
{"a":2,"b":5}
and I want to return a set of possible values of B for each A, like this:
[{"a":1, "b":[2,3] },
{"a":2, "b":[5] }]
Trying SELECT c.a, ARRAY(SELECT DISTINCT c.b FROM c) FROM c GROUP BY c.a
I receive the error
Property reference 'c.b' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
Same for ARRAY(select value c.b from c); and ARRAY_CONCAT does not look like an aggregate function.
Are there ways to do it without aggregating client-side?
Per my knowledge, this is not supported in Cosmos Db so far. Because Array is not aggregate function anyway which means it can't used with group by.
So, i suppose that you need to retrieve the data sort by a. Then loop the result to produce the b array mapping to the duplicate a.
For, Distinct values of b (output is in string format and values of b are comma separated)
SELECT a, String.Join(",", ARRAY_AGG(DISTINCT b)) AS list FROM c;
You can also use below, but the output format is not readable
SELECT a, ARRAY_AGG(DISTINCT b) AS list FROM c;
I have two tables which look like such
Organizations
Id (primary_key. big int)
Name (text)
CustomInformations
Id (primary_key. big int)
ConnectedIdentifiers (JSONB)
Info (text)
CustomInformations's ConnectedIdentifiers column contains a JSONB structure which looks like
{ 'organizations': [1,2,3] }
This means that there's an array of organizations with those ids 1, 2, 3, which are related to that particular CustomInformation
I'm trying to do a JOIN where given a CustomInformation Id will also get me all the Organizations names
I tried this after looking at some examples:
SELECT * FROM CustomInformations ci
INNER JOIN Organizations o on jsonb_array_elements(ci.ConnectedIdentifiers->'19') = o.id
WHERE
ci.id = 5
I got an error No operator matches the given name and argument type(s). You might need to add explicit type casts.
Is this the right approach? And if so what is wrong with my syntax?
Thanks
You cannot use jsonb_array_elements() in this way because the function returns set of rows. It should be placed in a lateral join instead. Use jsonb_array_elements_text() to get array elements as text and cast these elements to bigint:
select ci.*, o.*
from custominfo ci
-- lateral join
cross join jsonb_array_elements_text(ci.connectedidentifiers->'organizations') ar(elem)
join organizations o
on elem::bigint = o.id
where ci.id = 5
I'm trying to join a table that might have multiple entries for the given id and aggregate the rows corresponding to this id in an array. This looks as follows in the SQL query:
SELECT * from data
LEFT JOIN (select id, array_agg(row(foo, bar)) AS foo_bar_data from foo_bar_table group by id) AS temp using(id)
This works as intended, but I'm having trouble reading out the result in JDBC.
ResultSet rs = st.executeQuery(...)
Array a = rs.getArray("foo_bar_data")
// Now I want to iterate over the array, reading the values foo and bar of each item.
My efforts so far always ended in a Method org.postgresql.jdbc4.Jdbc4Array.getArrayImpl(long,int,Map) is not yet implemented. exception. How can I iterate over a, retrieving the values foo and bar?
Edit: I should possibly also mention, that foo and bar don't have the same type.
Postgres JDBC driver does not support anything except basic types (numbers, date/timestamp, string) as JDBC array. You can call array_agg twice and get two arrays on each row:
try (Connection db = DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres", "postgres", "postgres");
ResultSet rs = db.createStatement().executeQuery("select array_agg(i), array_agg(s) from (select 1 i, 'a' s union select 2 i, 'b' s) t")) {
rs.next();
System.out.println(Arrays.toString((Object[]) rs.getArray(1).getArray()));
System.out.println(Arrays.toString((Object[]) rs.getArray(2).getArray()));
}
I have the next query which does not work:
UPDATE item
SET popularity= (CASE
WHEN (select SUM(io.quantity) from item i NATURAL JOIN itemorder io GROUP BY io.item_id) > 3 THEN TRUE
ELSE FALSE
END);
Here I want to compare each line of inner SELECT SUM value with 3 and update popularity. But SQL gives error:
ERROR: more than one row returned by a subquery used as an expression
I understand that inner SELECT returns many values, but can smb help me in how to compare each line. In other words make loop.
When using a subquery you need to get a single row back, so you're effectively doing a query for each record in the item table.
UPDATE item i
SET popularity = (SELECT SUM(io.quantity) FROM itemorder io
WHERE io.item_id = i.item_id) > 3;
An alternative (which is a postgresql extension) is to use a derived table in a FROM clause.
UPDATE item i2
SET popularity = x.orders > 3
FROM (select i.item_id, SUM(io.quantity) as orders
from item i NATURAL JOIN itemorder io GROUP BY io.item_id)
as x(item_id,orders)
WHERE i2.item_id = x.item_id
Here you're doing a single group clause as you had, and we're joining the table to be updated with the results of the group.
I am trying to create an Entity SQL that is a union of two sub-queries.
(SELECT VALUE DISTINCT ROW(e.ColumnA, e.ColumnB, 1 AS Rank) FROM Context.Entity AS E WHERE ...)
UNION ALL
(SELECT VALUE DISTINCT ROW(e.ColumnA, e.ColumnB, 2 AS Rank) FROM Context.Entity AS E WHERE ...)
ORDER BY *??* LIMIT 50
I have tried:
ORDER BY Rank
and
ORDER BY e.Rank
but I keep getting:
System.Data.EntitySqlException: The query syntax is not valid. Near keyword 'ORDER'
Edit:
This is Entity Framework. In C#, the query is executed using:
var esql = "...";
ObjectParameter parameter0 = new ObjectParameter("p0", value1);
ObjectParameter parameter1 = new ObjectParameter("p1", value2);
ObjectQuery<DbDataRecord> query = context.CreateQuery<DbDataRecord>(esql, parameter0, parameter1);
var queryResults = query.Execute(MergeOption.NoTracking);
There is only a small portion of my application where I have to resort to using Entity SQL. Generally, the main use case is when I need to do: "WHERE Column LIKE 'A % value % with % multiple % wildcards'".
I do not think it is a problem with the Rank column. I do think it is how I am trying to apply an order by to two different esql statements joined by union all. Could someone suggest:
How to apply a ORDER BY to this kind of UNION/UNION ALL statment
How to order by the non-entity column expression.
Thanks.